If your RDP client is slow to connect and just says Just a moment before giving you the option to log in, then you’ve probably got an RDP client that’s expecting to communicate with NLA (Network Level Authentication), but connecting to a server that doesn’t support it.

To fix the slow RDP client and get rid of the Just a moment message, either disable NLA in the RDP client or enable NLA on the server you are connecting to (preferable).

Note that disabling NLA on the client will make the connection less secure.